A study on the relationship of phase equilibrium and electromechanical properties in the modified PbTiO/sub 3/-BiFeO/sub 3/ system

In the modified PbTiO/sub 3/-BiFeO/sub 3/ system, there is a morphotropic phase boundary (MPB) between the tetragonal and rhombohedral phases. The electromechanical properties of ceramics with composition near the MPB were examined. It is shown that, when the BiFeO/sub 3/ content is within 57.5-60 mol.%, there is a mutation of electromechanical properties in the modified PbTiO/sub 3/ system, making them similar to those of the PbTiO/sub 3/-PbZrO/sub 3/ system. In order to explain this mutation, the microstructure, domain structure, and electron diffraction of samples were observed by scanning electron microscopy (SEM). It was found that the special microstructure, domain structure, and one-dimensional superlattice observed in the samples may be the cause of the excellent electromechanical properties of these ceramics.<
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